Alexander Litvinenko's son told an inquiry into his death that he "never truly believed" his father would die and that he was "hit hard" by the news.

Twenty-year-old Anatoly Litvinenko was 12 when his father died. He told the court, "Before this point I never truly believed my father would die. I was young and optimistic and I thought he would recover."

A court sketch of Anatoly Litvinenko, the son of Alexander Litvinenko. Credit: ITV News/Priscilla Coleman

He told the inquiry that his father's death "hit me hard, but at the same time I felt quite numb ... It was very painful to look at him in the state he was in."

Alexander Litvinenko's widow wept today as she recalled the last words she heard him utter before his death, "I love you so much".

Recounting the disturbing days leading up to his death, Marina Litvinenko told the inquiry into her husband's death that he converted to Islam from his bed so he could be buried in Chechen soil.

Alexander Litvinenko's widow Marina wept as she spoke at the inquiry into his death. Credit: ITV News/Priscilla Coleman

The former Russian spy, who worked for British intelligence services during his time in the UK, died at University College Hospital nearly three weeks after he consumed tea laced with polonium-210 at the Millennium Hotel in London's Grosvenor Square.

Two men - former KGB bodyguard-turned-politician Andrei Lugovoi and Dmitri Kovtun - were named as the main suspects in 2007. Both deny any involvement and remain in Russia.

Asked who she blamed for her husband's death, Marina Litvinenko told the inquiry:

I tried to be very objective and not to blame just because what I do feel and what I do believe...
When the police said in fact that they blamed Lugovoy and Kovtun and they have this evidence I said, 'Yes, I agree, and I agree with this investigation.'

Marina Litvinenko told the inquiry that her husband accused Russian president Vladimir Putin of being a paedophile.

The inquiry at the Royal Courts of Justice in central London was shown a copy of the article which featured a photograph of Mr Putin and the boy and the headline 'Kremlin Paedophile'.

Giving evidence today, Mrs Litvinenko, said: "It was written in 2006 after everybody saw how Putin behaved when he met a little boy in a Kremlin tour group. He went under his t-shirt and kissed his stomach."

Robin Tam QC, counsel to the inquiry, said: "You have no idea if that allegation is true?"